CLI Reference Guide-R05

Chapter 11 | Interface Commands
Power Savings
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Example
Console#show cable-diagnostics interface ethernet 1/10
TF: Test failed
OK: OK
ON: Open
ST: Short
IE: Impedance error
NC: No cable
NT: Not tested
NS: Not supported
UN: Unknown
Port Type Link Pair A Pair B Pair C Pair D Last
Status meters meters meters meters Updated
-------- ---- -------- -------- -------- -------- -------- -------------------
Eth 1/2 GE Down NC (0) NC (0) NC (0) NC (0) 2000-12-31 08:28:59
Console#
Power Savings
power-save This command enables power savings mode on the specified port. Use the no form
to disable this feature.
Syntax
[no] power-save
Default Setting
Enabled
Command Mode
Interface Configuration (Ethernet)
Command Usage
◆ IEEE 802.3 defines the Ethernet standard and subsequent power requirements
based on cable connections operating at 100 meters. Enabling power saving
mode can reduce power used for cable lengths of 60 meters or less, with more
significant reduction for cables of 20 meters or less, and continue to ensure
signal integrity.
◆ Power saving mode only applies to the Gigabit Ethernet ports using copper
media.
◆ Power savings can be enabled on Gigabit Ethernet RJ-45 ports.
◆ The power-saving methods provided by this switch include:
■
Power saving when there is no link partner:
Under normal operation, the switch continuously auto-negotiates to find a
link partner, keeping the MAC interface powered up even if no link
connection exists. When using power-savings mode, the switch checks for
energy on the circuit to determine if there is a link partner. If none is